Now, we considered \(\phi (0)=cte \) , thus \(M(r)\)  will be as follows[1]}:
\(M(r)=&&a_{1}r+a_{2}r^{2}+a_{3}r^{3}+a_{4}r^{4}+a_{5}r^{5}+a_{6}r^{6}\nonumber \\&&+a_{7}r^{7}+a_{8}r^{8}+a_{9}r^{9}.\) 
